Fewer kidney patients have received gadolinium contrast dyes during MR studies since the US Food & Drug Administration (FDA) first issued warnings about their association with nephrogenic systemic fibrosis (NSF) in 2006. NSF is a condition involving the formation of excess fibrous connective tissue in the skin, joints, eyes, and internal organs that can be fatal. Evidence suggests that NSF is most likely to occur in people with severe kidney disease who have been exposed to a gadolinium contrast dyes.

Gadolinium contrast dyes are sold under the names Ablavar, Eovist, Magnevist, Multihance, Omniscan, Optimark, and Prohance. In 2007, the FDA mandated that all gadolinium agents sold in the US carry a black box warning â€“ the agencyâ€™s strongest safety notice â€“ regarding the risk of NSF. This past September, the FDA ordered the warning be strengthened.

All gadolinium contrast dye labels will now emphasize the need to screen patients to detect these types of kidney dysfunction before administration, the FDA said. Three of the dyes which the FDA said are associated with a greater risk of NSF compared to the other agents, Bayer Healthcareâ€™s Magnevist, GE Healthcareâ€™s Omniscan, and Covidienâ€™s Optimark, will be described as inappropriate for use among patients with acute kidney injury or chronic severe kidney disease.

According to a new study published in the American Journal of Kidney Diseases, the rate at which patients with kidney disease are exposed to gadolinium agents has dropped significantly since the initial FDA alert was issued. The study looked at patients receiving medical care in the US Department of Veterans Affairs Health Care System. From July 2005 to September 2008, a total of 1,080,536 MR studies were performed. Of these, 406,003 (38 percent) were gadolinium-enhanced MR studies

From the first warning in 2006 through the fourth quarter of 2008, the usage of gadolinium agents in patients undergoing MR studies was essentially unchanged for patients with a glomerular filtrate rate (GFR), a measurement of kidney function, above 60. The rate declined, however, by 71 percent for those with a GFR of 15-30 and 61 percent for patients with a GFR of 15 or less. A GRF under 30 is indicative of kidney failure. Patients with a GFR of 15 or less must undergo dialysis

In addition, the rate declined 81 percent among subjects who had received recent dialysis (98 percent for a subset of patients with acute kidney injury).

Meanwhile, the rate of use of non-gadolinium MR agents increased for all GFR categories, except for patients who had received recent dialysis. The rate rose by 19 percent for patients with a GFR of 15-30 and by 71 percent for those with a GFR of 15 or below.

In addition, it appears that clinicians began screening patients for kidney issues prior to their MR studies after the FDA issued its first gadolinium alert in 2006. During the time frame covered by the study, the proportion of gadolinium enhanced MR studies with serum creatinine measurements – a test used to measure GFR – obtained within one month, three months, and six months prior to the study increased by 99 percent, 59 percent and 41 percent.